Chipped case mouth?

[Jcub]

I don't know exactly how many times I've fired this lot of brass, it was my first lot that I reloaded for, but it is over 5x. How does this happen? Is it something that I did? Is it something wrong with my rifle? Or is the brass just had enough? I don't push my loads hard at all, I'm shooting 61.3 grains of Retumbo lately, out of a 24" bbl at 2745fps with a 168gr SMK.



All help is greatly appreciated gentleman.

 

[Jcub]

Is it right to believe that these cases are no longer desirable for precision hand loads?...

 

[mdmp5]

When you say chipped, do you mean dented? I have run into the same issue when sizing warped mouths with the expander ball and not being careful to ease the ball into the mouth.

The cases should be fine. Just make sure to chamfer the insides so any imperfections in the dents are not imparted on the bullet. After a few firings and if you don't create any more dents, they will be trimmed off and you will have normal looking brass again. Trim your cases now a bit to remove some of the dent

 

[RHunter]

I bet you don't anneal, that is metal fatigue.

 

[mdmp5]

I bet you don't anneal, that is metal fatigue.

Reason I don't think that is metal fatigue is because the small dents look the same in all the cases. I believe it is something systematically being done, like a impact on the mouth during sizing

 

[Juma]

Anneal and use CTS trimmer. Nice piece of kit.

 

[Advokaten]

IF it did occur efter sizing, then you might have some debrie in your die that causes that issue. /Chris

 

[milo 2.0]

Reason I don't think that is metal fatigue is because the small dents look the same in all the cases. I believe it is something systematically being done, like a impact on the mouth during sizing

I'm with this guy, though mine that get dinged are way more severe than this? Jcub, we kind of need more info as to when you notice these appearing. After firing, after sizing, after trimming, etc..

If it's during sizing, usually it's from ramming and jamming, slow down. My type "S" dies with the black retaining pin holder mess up enough cases when I get in a hurry, even neck sizing on a coax?

 

[RHunter]

Reason I don't think that is metal fatigue is because the small dents look the same in all the cases. I believe it is something systematically being done, like a impact on the mouth during sizing

Could be, its hard to tell from the photos...

Perhaps the OP could be a little clearer and tell us when this is happening. That might make it easier to figure out the issue.

 

[Jcub]

[MENTION=99308]Juma[/MENTION]- I have a Wilson micrometer case trimmer, don't need the 1 you offered.

I have never trimmed this brass, never had too.

I annealed this lot after it's 3rd firing.

To be honest, I can't recall if I noticed it after firing last weekend, or when I took them out of my tumbler. [MENTION=25934]mijp5[/MENTION] you are probably right. I could be running the brass into my die with too much force. When I get home today I will check and clean my die. I am using a standard FL die set from RCBS. I have an old RCBS Rockchucker press.

Thank you for the replies gentleman, they are greatly appreciated.

 

[Sniper260]

I had some wincheater brass doing that pretty bad. I threw it away... i couldnt figure out what was going on... i chalked it up to bad brass and/or a trimmer problem. It was with wincheater 243 brass.... be sure to measure your oal case length... many time you dont need to trim a ton...

 

[damoncali]

Just looks like a ding to me. I'd guess its from extraction, ejection, sizing or seating. Could be hitting something on the rifle, or a piece of crud in the dies.

 

[Jcub]

Thanks for really narrowing it down for me [MENTION=50186]damoncali[/MENTION]. Haha

 

[bigedp51]

I have never trimmed this brass, never had too.

There was a old TV cigarette commercial about Chesterfield 100 being "a silly millimeter longer".

You stated you have never trimmed your cases, could your cases be "a silly millimeter longer" and the case mouth hitting the action on ejection? (And this is my No.1 guess)

If thats not the problem then you may have a chunk of brass sticking to the expander button. Its amazing how rough things look when you take a macro photo and enlarge it.

Not to change the subject but looking at the rough coarse threads its no wonder its so easy to lock down the expander button off center and have increased runout.